2 points to make:
1.
7% is a lot, but you have to keep in mind the guys winning by that margin would likely be winners at 10 x that stake.
Why wouldn't they play higher I hear you say.
Depends on life circumstances in many cases.
I hear Chimera only plays poker to fund his Duvel & momo habbit, Degen. Discount him.
Lac for example has a family to support and lives in low cost Thailand, solid low variance money from $7/15 which requires a much smaller BR is better for his life than the crazy variance of a 0% roi @$100 $20,000 downswing etc.
Which brings me onto my 2nd point -
warning, an unwelcome truth follows...
A lot of guys are always asking about variance of various formats.
Seems like a fair enough question, but the truth is, the variance of ANY FORMAT is so directly related to your edge in the games, that to a player who needs to ask about variance in different formats, the variance of all of them will likely be very high.
Harsh but true I'm afraid.
Pick a format by assessing personal stengths, attainable edge & game liquidity, then work like a son of a gun to become the best possible player you can ever be at that format, and don't sweat the variance.
The dream of variance free poker just does not exist my friend, you just gotta make the best of what does